3. The main jet adjustment (14) 2-1/2 turns open (to left) from seat.
ADJUSTMENTS
If the engine, after running satisfactorily, suddenly ceases to perform properly, look over the intake manifold
and the carburetor flange gaskets, throttle, choke and fuel connections. Make sure that throttle and choke
valves open and close correctly and that fuel enters the carburetor in a free and steady stream. Do not
change carburetor adjustments until other causes of trouble have been investigated.
Changes in adjustment should be necessary only with change in fuel or climate.
Before making any adjustments, warm up the engine thoroughly so that the intake manifold feels warm to
the hand.
IDLE AND LOW SPEED ADJUSTMENT
Close the throttle slowly until desired idling speed is reached.
Turn idling needle valve (6) gradually to right and left until the engine runs steady and as fast as this
throttle position will permit.
Turning the idling needle valve to right (in) makes the mixture richer, to left (out) makes the mixture leaner.
If a satisfactory adjustment cannot be obtained, examine the idling jet (5) and the idle discharge plug (8) to
make sure that dirt or water does not obstruct the free flow of the moisture through these parts.
After completing the adjustments set throttle stop screw (12) for desired idling speed.
INTERMEDIATE AND HIGH SPEED ADJUSTMENT
The mixture at intermediate and high speed is controlled by the main jet (2), and the wall vent (4).
The main jet may be either of fixed size or adjustable. Whether fixed or adjustable, remove main jet (2) and
blow out with compressed air or rinse in clean gasoline to remove water or dirt which may obstruct the
metering orifice.
If adjustable, adjustment should be made as follows: (i) Open throttle about one-third; (ii) loosen packing
nut on main jet adjustment (14); (iii) turn main jet adjustment to right (in) until the engine speed is
noticeably reduced; (iv) turn main jet adjustment slowly to left (out) until the engine runs smoothly and as
fast as this throttle position will permit; (v) hold needle valve in position and tighten packing nut after
completing the adjustment.
Compensation is controlled by the well vent (4). A richer mixture, at high speeds is obtained with a smaller
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